Chiral Resolution of the Enantiomers of New Aromatase Inhibitors by Liquid Chromatography on Amylose Stationary Phases

Analytical HPLC methods for derivatized amylose chiral stationary phases were developed for the direct enantioseparation of substituted [1-(imidazo-1-yl)-1-phenylmethyl)] benzothiazolinone and benzoxazolinone derivatives with one stereogenic center. These analogues of fadrozole constitute new potent nonsteroidal inhibitors of aromatase (P450 arom.). The separations were made using normal phase methodology with mobile phase consisting of n-hexane-alcohol (ethanol, 1-propanol or 2-propanol) in various proportions, and a silica-based amylose tris-3,5-dimethylphenylcarbamate (Chiralpak AD), or tris-(S)-1-phenylethylcarbamate (Chiralpak AS). The effects of concentration of various aliphatic alcohols in the mobile phase were studied. Baseline separation (R_s > 1.5) was easily obtained in all cases, ethanol being often the more interesting modifier. The effects of structural features of the solutes along with the temperature of the column on the discrimination between the enantiomers were examined for different mobile phase compositions.     

Reversed-Phase Liquid Chromatographic Separation, on Cellulose Chiral Stationary Phases, of the Stereoisomers of Methoxytetra-hydronaphthalene Derivatives, New Agonist and Antagonist Ligands for Melatonin Receptors

A stereoselective high-performance liquid chromatographic method has been established for chiral separation of melatoninergic derivatives with one or two chiral centers, new agonist and antagonist ligands for melatonin receptors. Reversed-phase separations were performed on cellulose-based chiral stationary phases—tris-3,5-dimethylphenylcarbamate (Chiralcel OD-RH) or tris-methylbenzoate (Chiralcel OJ-R). Water–modifier (methanol or acetonitrile) mixtures in different proportions were used as mobile phases. The effects of organic mobile-phase modifier concentration, temperature, and compound structure were examined. Baseline separation (R_S > 1.5) was readily obtained for many of the compounds.     

Chiral Resolution of Benzophenone Imine Derivatives of Amino Acid Esters on Chiral Stationary Phases

Abstract

A convenient way of resolving the enantiomers of amino acid esters after their derivatization using benzophenone imine is described. The enantiomers of benzophenone Schiff base derivatives of various amino acid ethyl esters are readily separated on three commercially available chiral stationary phases (CSPs). Among them, CSPs 2 and 3 afford generally the base-line enantioresolution for the analytes studied. From understanding of chromatographic results, a plausible chiral recognition mechanism is discussed.     

联萘衍生物作为手性固定相在高效液相色谱中的应用

光学活性的联萘衍生物以其独特的立体化学性质作为优异的C2轴手性诱导源,已被广泛地应用到不对称催化反应和手性识别中。综述了联萘衍生物作为手性固定相在高效液相色谱中的应用。引用文献54篇。     

高效液相色谱手性固定相对氨基酸衍生物对映体分离研究

利用高效液相色谱手性固定相对光学异构体分离分析日益受到人们的重视。高效液相色谱氨基酸酰胺型手性固定相对拆分对映异构体具有较好的效果。本文为了探讨该类手性固定相对氨基酸的拆分影响,用L-异亮氨酸叔丁酰胺型手性固定相,对6种DL氨基酸(丙氨酸、2-氨基-n-丁酸、缬氨酸、亮氨酸、苯丙氨酸和蛋氨酸)的18种衍生物进行了拆分,并讨论了其衍生物取代基对手性拆分的影响及从立体化学角度提出了手性拆分机理。实验结果表明,这种手性固定相对外消旋氨基酸衍生物有较好的拆分能力。 1 实验部分 1.1 仪器和试剂 Varian 2010型高效液相色谱仪(美国);2050型紫外检测器及HP3394型积分仪(美国);L-异亮氨酸叔丁酰胺型手性柱(TBILS,上海药物研究所),粒度10μm,柱长100mm、内径4mm的不锈钢柱。 异丙醇(分析纯)用前重蒸,石油醚(60～90℃)分析纯,重蒸收集69℃镏分,用前全经过0.5μm薄膜并脱气。DL-氨基酸衍生物[丙氨酸(Ala),2-氨基-n-丁酸(Buty),缬氨酸(Val),亮氨酸(Leu),苯丙氨酸(Phe),蛋氨酸(Met)]用相应DL-氨基酸参考文献方法进行N-乙酰化及酯化。衍生物经元素分析合格,配制成5mg/mL溶液。     

手性固定相高效液相色谱法拆分系列抗胆碱能药物对映体的研究

采用手性固定相高效液相色谱法研究了甲醇-磷酸盐体系、乙腈-磷酸盐体系和甲醇-乙腈-磷酸盐体系对系列抗胆碱能药物的手性拆分情况,讨论了流动相的各个因素（有机相的种类和比例、磷酸盐浓度、酸度、三乙胺用量等）对手性拆分的影响。研究表明,流动相中较大的水相比例、较高的磷酸盐浓度、pH和三乙胺浓度更有利于抗胆碱能药物的手性拆分。通过对比研究10种抗胆碱能手性药物的色谱行为,从结构上讨论了化合物中不同官能团对保留时间及手性拆分的影响,并探讨了手性拆分的内在机制。     

纤维素衍生物手性固定相用于高效液相色谱对映体分离

纤维素衍生物是目前高效液相色谱 (HPLC)中应用最为广泛的手性固定相之一 ,对各种类型的外消旋体都表现出了很高的对映体选择性 ,因其负载量大特别适用于对映体制备分离。本文对纤维素衍生物手性固定相的种类、影响手性选择性的因素以及手性识别的机理进行了较为全面的评述 ,并展望了研究前景     

H PLC聚合物手性固定相

对近年来文献报道的高效液相色谱聚合物手性固定相及其在手性拆分中的应用予以综述 ,并阐述了聚合物手性固定相拆分机理的研究进展。     

高效液相色谱中的纤维素衍生物手性固定相

评述了高效液相色谱中纤维素衍生物手性固定相直接拆分对映体的进展，介绍了纤维素衍生物的主要类型，纤维素衍生物作手性固定相三种不同方式的特点以及新的纤维素衍生物手性固定相应用，并结合色谱，NMR和分子模型设计和理论计算等方法讨论了纤维素衍生物手性固定的拆分机理。     

高效液相色谱手性聚合物固定相的研究与进展

对近年来高效液相色谱手性固定相的研究进行了综述。重点介绍了手性聚合物固定相的分类和应用的新进展。讨论了各类手性固定相优缺点,提出了目前存在的问题和今后研究的方向和重点。     

Effect of Chiral Additives in the Preparation of Cellulose-Based Chiral Stationary Phases in HPLC, and Effect on Enantiomer Resolution

Chiral stationary phases (CSPs) for high-performance liquid chromatographic (HPLC) have been prepared by coating silica gel with cellulose tribenzoate or cellulose trisphenylcarbamate. The effect of chiral additives on preparation of the CSPs was studied with (+)-l-mandelic acid, (−)-2-phenyl-1-propanol, (+)-1-phenyl-1,2-ethanediol and (−)-1-(1-naphthyl)ethanol as chiral additives for cellulose tribenzoate and (−)-2-phenyl-1-propanol and (+)-phenylsuccinic acid as chiral additives for cellulose trisphenylcarbamate. The results showed that chiral recognition by these stationary phases was increased in comparison with the original CSPs, especially the resolution (R _S) obtained. The method can be used to improve the efficiency of enantiomer separation by silica gel stationary phases coated with polymers.     

万古霉素键合手性固定相高效液相色谱法直接分离泰妥拉唑对映体

利用反相高效液相色谱法在大环抗生素类手性固定相万古霉素键合手性固定相(Chirobiotic V)上直接分离了泰妥拉唑对映体。考察了缓冲溶液的种类、浓度和pH值,有机改性剂的种类和浓度,柱长和柱温等对手性分离的影响。优化后的色谱条件为:Chirobiotic V色谱柱(150 mm×4.6 mm,5 μm),流动相为0.02 mol/L 醋酸铵缓冲液(pH 6.0)-四氢呋喃(体积比为93∶7),流速为0.5 mL/min,柱温为20 ℃,检测波长为306 nm。在此条件下泰妥拉唑对映体达到了基线分离,分离度达1.68;对映体保留时间的相对标准偏差分别为0.48%和0.49%(n=6),峰面积的相对标准偏差分别为0.45%和0.55%(n=6)。所建立的手性分离方法具有简便快速及重复性好等优点。     

纤维素类手性固定相及高效液相色谱-旋光仪联用技术的研究

合成了3种纤维素衍生物并分别填充分析型色谱柱,研究了不同的涂敷条件对柱效的影响以及色谱柱的稳定性,对外消旋化合物进行了手性拆分。实现了高效液相色谱－旋光仪的联用,获得了在线旋光曲线。     

Separation of Enantiomers of Isochromene Derivatives by HPLC Using Cyclodextrin-Based Stationary Phases

Twenty chiral isochromene derivatives have been chromatographed on native and derivatized cyclodextrin stationary phases using HPLC. The most effective CSPs for the enantioresolution of these analytes in the reverse phase mode are the hydroxypropyl--cyclodextrin (Cyclobond RSP), the 2,3-dimethyl--cyclodextrin (Cyclobond DM), and the -cyclodextrin (Cyclobond II) stationary phases. The -cyclodextrin (Cyclobond III), -cyclodextrin (Cyclobond I), acetyl--cyclodextrin (Cyclobond AC), S-1-naphthylethyl carbamate--cyclodextrin (Cyclobond SN), and 3,5-dimethylphenyl carbamate--cyclodextrin (Cyclobond DMP) stationary phases also show enantioselectivities for some analytes. No enantioseparations were observed in the polar organic mode and only a few separations were found in the normal phase mode. The Cyclobond RSP CSP provided the best overall separations of these analytes in the reverse phase mode. The pH of the mobile phase and the nature of organic modifiers have little effect on the enantioresolution. The substituents on the isochromene ring greatly affect the chiral recognition.     

Enantioseparation of Amino Acid Derivatives with a Cellulose-Based Chiral Stationary Phase

Five structurally related amino acid derivatives were enantioseparated by HPLC with a commercially available chiral stationary phase, Chiralcel OD-H. The chromatographic experiments were performed in the normal phase mode. n-Hexane/polar alcohol was used as mobile phase. Excellent baseline enantioseparations could be obtained for all these solutes. The effects of the concentration of polar alcohol and the column temperature on the retentions and enantioseparations were studied in detail. From the van't Hoff plots the corresponding apparent thermodynamic parameters were derived. Mechanism aspects of chiral recognition were discussed based on the relationship between the thermodynamic parameters and the structures of the solutes. It was found that the substituent of the phenyl group on the residual group of the amino acid derivatives was close relevant to thermodynamic origin of enantioseparation. Much better enthalpy–entropy compensation effect was obtained by plotting the differential, rather than the original, thermodynamic parameters.     

高效液相色谱手性固定相法拆分克伦特罗对映体

以正己烷、异丙醇为流动相,用Whelk-O1手性固定相成功拆分了药物克伦特罗对映体。出峰时间在5min左右,峰形对称性好,完全达到基线分离,分离因子大于1．4,可用于该对映体药物的分析与制备分离。讨论了二元流动相中异丙醇含量及温度的变化对分离的影响,并对拆分机理进行了探讨。     

环糊精衍生物气相色谱手性固定相研究进展

评述近年环糊精衍生物气相色谱手性固定相的研究进展,对环糊精衍生物进行分类并总结了近年来其在GC手性分离上的应用,介绍环糊精衍生物的手性分离机制及纯度问题进展,展望环糊精衍生物作GC手性固定相的应用前景。     

Chiral Separation of Racemates of Drugs and Amino Acid Derivatives by High-Performance Liquid Chromatography on a Norvancomycin-Bonded Chiral Stationary Phase

A novel norvancomycin-bonded chiral stationary phase (NVC-CSP) has been synthesized by use of the chiral selector norvancomycin, which differs from vancomycin because of the presence of leucine rather N-methylleucine. The enantiomers of some neutral and basic chiral drugs, for example warfarin, benzoin, bendroflumethiazide, and praziquantel, were directly separated by high-performance liquid chromatography in the reversed-phase mode. The effect of conditions such as organic modifier concentration, column temperature, pH, and mobile phase flow rate on retention and enantioselectivity were investigated. It was shown that hydrophobic, steric, and ionic interactions were present between the analyte and the macrocycle in this chromatographic system. Vant Hoff plots afforded the thermodynamic data _R,SH° and _R,SS°; the negative values obtained indicated the process of enantiomer separation was enthalpy-controlled. In an attempt to improve the resolution of some very polar acidic compounds (dansyl-amino acids) norvancomycin was used as stationary phase chiral selector and chiral mobile-phase additive simultaneously, better results were obtained as the result of a synergistic effect. It was also shown experimentally that the newly synthesized NVC-CSP behaved somewhat differently from the earlier reported vancomycin-bonded CSP, probably because of the different structures of norvancomycin and vancomycin.     

涂敷三苯基氨基甲酸纤维素酯高效液相色谱手性固定相的制备和对映异构体分离

微晶纤维素与异氰酸苯酯在４－Ｎ，Ｎ－二甲基氨基吡啶催化下反应合成三苯基氨基甲酸纤维素酯，反应温度低，反应时间短；以平均粒径６μｍ、平均孔径１５ｎｍ、比表面积６７ｍ２／ｇ的堆积硅珠做担体，涂敷１５％（质量分数）三苯基氨基甲酸纤维素酯在上述担体上制备手性固定相；以此手性固定相高效液相色谱法直接分离（±）－２，２，２－三氟－１－（９－蒽基）乙醇对映异构体，确定了对映异构体的出峰顺序．